The assault weapons stuff is what they go after because it's low-hanging fruit. They know they can't successfully go after handguns, so they go after the scarier weapons, even though they aren't what's really causing the problems at the moment.

'Twas a cutlass swipe or an ounce of lead
Or a yawing hole in a battered head
And the scuppers clogged with rotting red
And there they lay I damn me eyes
All lookouts clapped on Paradise
All souls bound just contrarywise, yo ho ho and a bottle of rum!